PhD Defense by Georgiana-Laura Paraschiv

Georgiana-Laura Paraschiv, Department of Chemistry and Bioscience will defend her thesis on: "Structure and Physical Properties of Oxynitride Glasses"

Time

03.11.2017 kl. 13.00 - 03.11.2017 kl. 16.00

Description

TITLE:

"Structure and Physical Properties of Oxynitride Glasses"

ABSTRACT:

Glass is one of the most versatile materials available in the modern world. The advent of smart and wearable electronics, electric-powered technology and improved optics is demanding greater performances from glassy materials, e.g. enhanced portability and damage resistance. Thus tougher, stronger and durable glasses are required. This is can be achieved through designing new glasses with improved properties.

The effects of incorporated nitrogen over the glass properties were probed by the means of differential scanning calorimetry (DSC), various spectroscopic methods and indentation analysis. The evolution of hardness with nitrogen was investigated by the means of topological considerations.

The nitrogen-for-oxygen substitution is generating structural changes within the oxynitride glass network, thus causing significant modifications of the glass properties. Some properties exhibited a linear relationship with nitrogen content (e.g. density, glass transition temperature, harness), while others (e.g. liquid fragility) have shown a more complex compositional dependence. Addition of a secondary network former oxide in phosphate glasses generates more complex structural features. The presence of nitrogen alters the glass structure in terms of short-range order, but also intermediary-range order.